If you know the enemy and know yourself, you need not fear the result of a hundred battles. If you know yourself but not the enemy, for every victory gained you will also suffer a defeat. If you know neither the enemy nor yourself, you will succumb in every battle.

— Sun Tzu

The enemies we fight in these long wars our nation is now waging are not “warped [and] twisted,” as President Obama said during his April 30 press conference.

This characterization creates a misperception that weakens our ability to fight a very human, reasoned, foe.

Demonizing and dehumanizing the enemy is an old and familiar practice. It’s an effective means of simplifying a conflict for the public, instilling a sense of victimization and taking the moral high ground.

We called Germans Rhine monkeys and krauts. The Japanese nips, the Viet Cong slopes and Charlie. In Iraq and Afghanistan we took an Arabic term of respect, haji, and derisively applied it to the entire population.

But in the process of dehumanizing the enemy in our own minds, we lose sight of the fact we’ve done nothing to change them.

We’ve only changed ourselves, and how we see them. They remain as human as ever. As human as we.

As a Marine Corps counterintelligence specialist and interrogator in Iraq in 2003 and 2004, I had the opportunity to not just fight the enemy, but become intimately familiar with him:

— On the battlefield, the enemy is faceless, just someone who is trying to kill you. Someone you have to kill first.

— In the interrogation booth, the enemy is a man you have to connect with, relate to, even empathize with.

After conducting more than 400 interrogations as well as working with Iraqi informants, I’ve had the opportunity to see the enemy as he is, a human being with a range of motivations, loyalties and ideologies. I discovered the enemy isn’t crazy, or immoral, or twisted, though his reasoning may be alien to the Western understanding of sanity and morality.

I believe – as Sun Tzu did – that it is fundamentally dangerous to fail to see the enemy as he truly is.

Whether the specific enemy is a Shia insurgent in Iraq, the Sunni Taliban, al Qaeda and its global affiliates, or self-radicalized Islamists on our own soil, is irrelevant. To call them crazy underestimates the enemy’s cunning and intellect. To call them twisted, warped or immoral is arrogance.

These terms give us a false sense of superiority, narrow our thinking, and leave us vulnerable to attacks from an enemy that doesn’t conform to how we think they should look and act.

The recent Boston Marathon bombings are a good example. For many Americans, it was shocking to learn how the brothers Tsarnaev looked and acted so normal before their vicious attack. Many Americans have difficulty squaring their normalcy with their actions.

For me, there is no difficulty. The Tsarnaevs didn’t act normal, they were normal. Within their worldview, their actions were justified and rational.

We [Americans] have been the cowards, lobbing cruise missiles from 2,000 miles away. That’s cowardly. Staying in the airplane when it hits the building — say what you want about it — it’s not cowardly.

“The enemy is immoral!” I hear people say. “Terrorists deliberately target civilians!” This is true.

But we kill civilians, too. While we don’t specifically target civilians (well, not since World War II, perhaps, though I’m sure some leeway existed in Korea and Vietnam), their deaths are collateral to our intended targets.

But our intentions mean little to our enemy. To them, our actions are no different than theirs.

From my perspective this is a classic “ends justifies the means” discussion, and a red herring. When we killed Abu Musab al-Zarqawi, the ruthless leader of Al Qaeda in Iraq, in 2006, we knew several women and children were in the house where he was meeting with his lieutenants. The general who ordered the airstrike knew they would die along with Zarqawi, and it was worth it.

I fully believe that our end — killing the enemy and protecting our citizens — does indeed justify killing civilians. But I doubt they see it that way.

I view deliberately targeting civilians as ruthless and vicious, but I don’t believe in passing any kind of moral judgment. War is ruthless and vicious. The enemy will kill us where and when he can, and he should expect the same from us. We should hunt and destroy the enemy wherever we can, so the Boston bombing is not repeated.

To do that effectively, however, we must see the enemy for what he is — a rational, calculating human who fights for a variety of reasons. Whatever his reasons, they are justified in his own mind.

Most importantly, we should understand that our fundamental reasons for fighting are the same as his. We both believe in our respective cause, in defending our nation, our families, our way of life. We must not cloud our understanding of the enemy by labeling him “warped” and “twisted.”

It may be unsettling to think of an enemy who commits heinous acts of terrorism as having motives not much different from our own, but Sun Tzu was right. We must understand our enemies if we are ever to have hope of defeating them.

J.E. McCollough is a Marine Corps combat veteran. He served from 1996 to 2005 and was a counterintelligence specialist. He is currently writing a memoir and resides in Portland, Ore.